Caucus-goers check in before casting their votes at Caesar’s Palace in Las Vegas.

Voters age 45-plus bolstered winners Hillary Clinton and Donald Trump in the Feb. 20 presidential nominating contests in Nevada and South Carolina.

Their votes were especially significant in Clinton’s narrow victory in Nevada’s Democratic caucuses, where older voters had a much higher turnout than younger ones. The results continued the huge generational split in the party’s matchup between Vermont Sen. Bernie Sanders and Clinton, the former New York senator and secretary of state.

The age contrast was less dramatic in South Carolina’s Republican primary, but Donald Trump owed his victory to older voters. The billionaire businessman carried their vote, while finishing in a virtual tie with Sens. Marco Rubio of Florida and Ted Cruz of Texas among voters younger than 45, according to the exit poll by the National Election Pool.

In the Nevada caucuses, Clinton led Sanders 74 percent to 24 percent among those 65 and older, and 61 percent to 36 percent among those 45 to 64, according to a poll of Democrats before they entered the caucus vote. By contrast, Sanders led 82 percent to 14 percent among voters 17 to 29, and 62 percent to 35 percent among those ages 30 to 44. Clinton won overall, 53 percent to 47 percent.

A key factor was that 28 percent of the Nevada Democrats were 65 or older, and 35 percent were 45 to 64. By contrast, the exit poll in New Hampshire, where Sanders won with 60 percent of the vote, showed that only 18 percent were 65 and older and 40 percent were 45 to 64.

The greater participation by older voters in this year’s early nominating contests is a significant contrast to the 2012 presidential election. According to the exit poll that November, 16 percent of all voters were 65 or older and 38 percent were 45 to 64.

The disproportionate participation by older voters also was notable in the South Carolina GOP primary, where 27 percent of all voters were 65 and older, and 46 percent were between 45 and 64, according to a detailed breakdown. Both Nevada and South Carolina have become the home of large retirement communities.

In New Hampshire, only 19 percent of GOP primary voters were 65 and older; 49 percent were 45 to 64.

Trump led the 65-plus group with 33 percent to 25 percent for Rubio and 17 percent for Cruz. He had a larger lead among those 45 to 64: 36 percent to 23 percent for Cruz and 19 percent for Rubio. In the unofficial total results, Trump took 32.5 percent to 22.5 percent for Rubio and 22.3 percent for Cruz.

Support from older voters was not enough to sustain former Florida Gov. Jeb Bush, who suspended his campaign after the South Carolina vote. The GOP exit poll showed that Bush got 12 percent among those 65 and older and 8 percent among those 45 to 64, but only 4 percent from each of the two younger age groups.